Liquid-forcing apparatus



April 12 1927. 1,624,827

C.L;BURmCK ETAL LIQUID FORCING APPARATUS Filed March 5. 1926 I 1s 19 1m AWAIVEY Patented Apr. 12, 1927.

j UNITED STATES PATENT; oFFlcE.'-

cmmnns LAURENCE mmnmx, or Lennon, AND Jorm nounucx wmnuan, on wannmoron, ENGLAND.

LIQUID-PORCH G APPARATUS.

Application filed larch 5, 1926, Serial No. 82,624, and in Great Britain August 19, 1925.

(.)ur invention relates to apparatus for delivering liquids from a closed container by means of compressed air pressure'on the li aid and varying the pressure automatica ly according to the height at which the delivery is to be effected. The invention applies more particularly to such apparatus as is used for spraying or flowing. on paints and other liquids in which the pressure at the-point of discharge must be kept more or less uniform although the operator may be working at varying altitudes or working with a long handled instrument delivering liquid at varying altitudes from the liquid container. The usual method of adjusting this ressure is with the well known form of regu ating valve in which a diaphragm re ceives the pressure of air within the container and a spring with adjusting nut for tension acts in resistance to the compressed air.

It will be obvious that an automatic control for the pressure on the liquid will save the operator much time and trouble usually required to adjust the spring tension for the pressure for various altitudes.

The method employed by us is broadly to utilize the pressure of a column of liquid of which the head varies with the delivery height to control-or actuate a pressure regulating device so as to vary the pressure'upon the liquid to be delivered as the delivery height is varied.

In carrying out our invention we provide an automatic regulating valve which controls the flow of the compressed air .to the container; this valve is operated or controlled by the combined action of the air pressure within the container and the pressure of a column of water, spirit or other liquid contained in a tubeor pipe which is connected to the delivery pipe so that the pressure varies with the height to which the delivery pipe is carried.

5 In order to obtain suflicient pressure on 1 the paint or liquid when viscous or heavy pigments are being delivered we secure to the valve gate two diaphragms a smaller one against which the air presses from within the container having a tendency toclose the valve gate and limit or restrict the pres- I sure on the paint and a lar er diaphragm against which the pressure 0 the column of water operates to open the gate and permit a higher pressure of-air upon the liquid in the air container. relative sizes of these diaphragms may Vary according to the viscosity or weight of the liquid to be delivered or to secure increased flow of liquid. A preferred embodiment of the invention 1s illustrated by the accompanying drawing and liquid reservoir fitted therewith.

Asillustrated any convenient form of spraylng device generally designated 1 is supplied with compressed air (or other suitable gas) from a main supply connection 2 through a flexible pipe 3; Liquid (paint, etc.) is also supplied under pressure from a flexible pipe 5."

Attached to the spraying device 1 is a chamber 6 to which is connected a pipe 7 leading to the chamber 8 formed above the large diaphragm 9 of the regulating device. This chamber 6, pipe 7 and chamber 8 contain water, spirit or other suitable liquid. A'smaller diaphragm 10 has its centre spaced from that of diaphragm 9 by the abutments 11, 12. The valve 13 is connected by a link or yolre 14 to the abutment 12; it is guided by adjustable perforated screwed bushes 15. 15 and may be provided with a spring 16 the strength of which is adjustable by movement of the upper bush 15. A facing washer 17- of leather or like is retained at the face of the valve 13 and is adapted to make a tight joint against the fixed air orifice com municating with the air passage 18 which is in turn in communication with the main air supply pipe 2 through a branch 19. A spring 20 acts upon the upper side of the diaphragm 9 and an adjustable air escape screw 21 is shown to enable the pressure on the liquid in the container 4 to be relieved by the escape of air therefrom.

In order that the chamber 6 may be closed showing in part-sectional elevation a.'spray container or pressure reservoir 4 through a against escape of liquid and at the same time 1 compensate for any suction effect that might be produced by a lowering of the fluid level due to downward movement of the diaphragm 9 a small very flexible diaphragm 22 is placed under the the cap 6, the latter being perforated so that the pressure on the upper side of the diaphragm 22 is the at mospheric or external pressure.

In operation the container 4 is placed at be conveniently attac any convenient level ing device and the 11 of the liquid acting'on diaphragm 9 is balanced by the upward force of the compressed air admitted to the chamber 4 through the valve and acting on the diaphragm 10. As the spray is lowered the valve tends to shut owing to the decreased llqllld column pressure and equilibrium is reached by the slow escape of air from the vent 21. Condltions become stable at any height when the escape from the vent is exactly compensated by admission of fresh air by the valve: 13.

It will be clear that adjustment of the spring 16 against the constant opposlng force of the spring 20 enables any desired initial tendency of the valve to be produced (either upward or downward) apart from the air and liquid pressure on the diaphragm. Preferably the setting will be such as to compensate for the slight reduction of effective pressure which takes place asthe' diaphragm 22 is strained, but the pressure of the liquid column may be supplemented or counteracted to'some extent as desired by suitable springadjustments.

lVhile we have described in detail a preferred embodiment of our invention we wish it to be understood that we d9 not wish the scope of the claims to be limited so as to exclude equivalent novel constructions and embodiments within the'scope of their language.

We claim 1 Apparatus of the kind set forth comprising the combination of a closed container for liquid, a delivery pipe connected to the container and adapted to be raised to different heights relatively to the container, means to vary the pressure within the container, a column of liquid, means to vary the effective head of sa d column with the height of said delivery pipe, and means controlled by the pressure of said column to operate the said means for varying the pressure within the container.

2. Apparatus of the kind set forth coniprising the combination of a closed container for liquid, a delivery device, a flexible pi e between the container and the delivery ii;- vice, a second flexible pipe containin liquid, means to retain the surface of sai second mentioned liquid near the delivery device, means adapted to admit compressed air to said container, and mechanism controlled by the head of liquid in the said second flexible pipe to operate the said means for admitting compressed air.

3. Apparatus of the' kind set forth comprising the combination of a container for fluid to be delivered, a valve for admitting compressed air to said container, 9. diaphragm acted upon by the pressure in said container and connected so as? to tend to close said valve as said pressure increases,

of liquid and means operated by'the varia-' tion of pressure of liquid in said pipe to tend to' open said valve as the said pressure of liquid increases.

a flexible pipe containing a fixed quantity 4. Apparatus of the kind set forth com tend to open said valve as said head incompressed air to said container, a diaphragm acted upon by the pressure in said container and connected so as to tend to close said valve as said pressure increases, a flexible pipe containing a fixed quantity of liquid, a second diaphragm subjected to the pressure, head of the liquid in said pipe to tend to open said valve as said head increases, the operative area of said first-named diaphra being greater than that of said second iaphragm.

6. Apparatus of the kind set forth comprising the combination of a container for fluid to be delivered, a valve for admitting compressed air to said container, a diaphragm acted upon by the pressure in said container and connected so as to tend to close said valve as said pressure increases, a

flexible pipe containing a fixed quantity of liquid and means operated by the variation of pressure of liquid in said pipe to tend to "1 open said valve as the said pressure of liquid increases, together with' means to maintain the effective upper level of the liquid in said flexible pipe at approximately the same level as that at which delivery is being efl'ected irrespective of variation in the delivery level.

7. Means to operate a pressure regulating device including a liquid column, a diaphragm subject to the pressure head of said column, means to vary the said pressure head by varyin the upper level of said column, and flexib e fluid-tight means enclosing the upper end of said column and having its outer side open to the external pressure, all' in combination with an airbrush and means to maintain the upper level of said column automatically at substantially the same level as the air brush as the level of the said air brush is altered in operation.

8. Means to force a liquid from a closed container to deliver it at a variable delivery height comprising, in combination with the container, a device to regulate the pressure within said container, and means to operate said device includin a liquid column, a diaphragm subject to t e'pressure head of said column, means to vary the said pressure head by varying the upper level of said column with the delivery height.

9. Means to force a liquid from a closed container to deliver it at a variable delivery height comprising, in combination with the container, a device to regulate the pressure within 'said container, and means to operate said device including a liquid column, a diaphragm subject to the pressure head of saidcolumn, means to vary the said pressure head by varying the upper level of said column with the delivery height, and a flexible fluid-tight closure enclosing the upper end of said column and having its outer side open to the external pressure. i

10. Apparatus of the kind set forth comprising the combination of a closed container said container, and mechanism controlled by the head of liquid in the said second flexible pipe to operate the said means for ad-. mitting. compressed air, together with an adjustable ventgiving a continuous but slight relief of pressure within the container.

11. Means to force a liquid from a closed container to deliver it at a variable delivery height comprising, in combination with the container pressure head means whereof the head is dependent upon the delivery height, means to admit compressed air to said container, an adjustable vent giving a continuous but slight relief of pressure within the container, difl'erential pressure means to operate the said air admitting means so that equilibrium is reached for any delivery height at a predetermined ratio of head to container pressure.

In testimony whereof we aflix our signatures.

CHARLES LAURENCE BURDICK. JOHN DOMINICK WHITEMAN. 

